osdn #42960: Target to freeciv-2.6.6: There's a bug that when a ship is inside a city (-> on land tile), and it attacks land units on surrounding land tiles, it does not count as land bombardment. This means that firepower adjustments are not made.
Unfortunately it's impossible to fix this properly in freeciv-2.6 or freeciv-3.0. The proposed fix has a downside, that with it then such ship's attacks from a city against Helicopters too count as land bombardment. I think this is the lesser evil.